Results of previous studies suggest that the timing of intravesical mitomycin C administration may impact bladder tumor recurrence rate following radical nephroureterectomy. This is the first study of its kind to attempt to identify the importance of timing of mitomycin C administration relative to bladder tumor recurrence rate following radical nephroureterectomy.This study will investigate the one year bladder tumor recurrence rate in patients with urothelial carcinoma of the upper urinary tract following intraoperative administration of mitomycin C during a nephroureterectomy, as well as the time to bladder tumor recurrence in this patient population.

Inclusion Criteria:

• Both males and females ≥ eighteen years of age
• Clinical diagnosis of urothelial carcinoma of the renal pelvis and/or ureter. Clinical diagnosis of urothelial carcinoma may be based upon radiographic, pathologic or cytological findings alone or in combination with one another. No other histology is allowed.
• The TNM stage of the subject's disease (using the American Joint Committee on Cancer [AJCC] Cancer Staging Manual, 8th Edition) must be Tis, Ta, T1, T2, or T3, N0, M0. Subjects may have either a high-grade or low-grade tumor.
• ECOG performance status of 0-2
• Written informed consent obtained from the subject and the ability for the subject to comply with all the study-related procedures.
• Women of childbearing potential (WOCBP) must be using an adequate method of contraception to avoid pregnancy prior to and for at least 3 months after mitomycin C instillation to minimize the risk of pregnancy. Prior to study enrollment, women of childbearing potential must be advised of the importance of avoiding pregnancy during trial participation and the potential risk factors for an unintentional pregnancy.
• Males with female partners of child-bearing potential must agree to use physician-approved contraceptive methods (e.g., abstinence, condoms, vasectomy) should avoid conceiving children prior to and for 3 months following mitomycin C instillation
• Subjects must have hemoglobin ≥ 9 g/dL and a platelet count ≥ 100,000/μL.

Exclusion Criteria:

• Active urothelial carcinoma of the bladder within 12 months prior to enrollment
• History of adverse reaction to mitomycin C
• Evidence of regional or metastatic disease.
• History of radical cystectomy
• Planned radical cystectomy at the time of nephroureterectomy
• Females or males of childbearing potential who are unwilling or unable to use an acceptable method to avoid pregnancy prior to and for at least 3 months after mitomycin C instillation.
• Females who are pregnant or breastfeeding.
• History of any other disease, metabolic dysfunction, physical examination finding, or clinical laboratory finding giving reasonable suspicion of a disease or condition that contraindicates the use of protocol therapy or that might affect the interpretation of the results of the study or that puts the subject at high risk for treatment complications, in the opinion of the treating physician.
• Prisoners or subjects who are involuntarily incarcerated.
• Subjects who are compulsorily detained for treatment of either a psychiatric or physical illness.
• Subjects demonstrating an inability to comply with the study and/or follow-up procedures

Adverse event data were collected, at a minimum, from the time of informed consent until 30 days after mitomycin C instillation. Adverse event data were collected for a maximum of 1,057 days for all participants.

Adverse events were assessed by the principal investigator, the treating sub-investigator, and/or the study coordinator from the time of informed consent until 30 days after mitomycin c instillation at a minimum. Adverse events were assessed by physical examination, labs, and subject self-reports.